Mr Varadkar yesterday sympathised with workers who were facing more inferior pensions than expected, but said strike action would not resolve the problem.

“I can understand where the Aer Lingus staff and where the airport workers are coming from; they’ve paid into their pensions all their lives and they’ve now found they’re not going to receive the pensions they hoped they would receive.”

However, he said many people in the public and private sectors were facing reduced pensions.

“They’re not the only ones in that boat. Most people in the country have either had their pensions reduced or their expectations for their pensions reduced and the only way we can solve this problem is by compromise on all sides and by talks and those talks are ongoing.”

The dispute centres on the Irish Airlines Superannuation Scheme, a pension pot operated jointly by Aer Lingus, the DAA and SR Technics, which has left Ireland.

The scheme, which has about 14,700 members, was running a deficit of about €700 million at the end of 2011, and talks have been taking place at the Labour Relations Commission since January in a bid to resolve the matter.

Siptu is to initiate action on September 20th unless progress is made in the talks. It is not clear what form of action might be pursued by the unions but it could potentially disrupt operations at Dublin, Cork and Shannon airports, and at Aer Lingus.

Mr Varadkar said progress could be made only through compromise and negotiation.

“A strike action isn’t going to resolve the pension deficit: that can only be done by compromise on all sides and that’s what needs to happen.”

Siptu president Jack O’Connor yesterday said the union’s members were frustrated by the lack of progress made in the talks and said industrial action was planned for September 20th.

“I am not able to comment on specific details. What I am able to say is that sanction has been given for industrial action on that date.”